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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This file defines all of the flags. It is separated into different section,
// for Debug, Release, Logging and Profiling, etc. To add a new flag, find the
// correct section, and use one of the DEFINE_ macros, without a trailing ';'.
// This include does not have a guard, because it is a template-style include,
// which can be included multiple times in different modes. It expects to have
// a mode defined before it's included. The modes are FLAG_MODE_... below:
// We want to declare the names of the variables for the header file. Normally
// this will just be an extern declaration, but for a readonly flag we let the
// compiler make better optimizations by giving it the value.
#if defined(FLAG_MODE_DECLARE)
#define FLAG_FULL(ftype, ctype, nam, def, cmt) extern ctype FLAG_##nam;
#define FLAG_READONLY(ftype, ctype, nam, def, cmt) \
static ctype const FLAG_##nam = def;
// We want to supply the actual storage and value for the flag variable in the
// .cc file. We only do this for writable flags.
#elif defined(FLAG_MODE_DEFINE)
#define FLAG_FULL(ftype, ctype, nam, def, cmt) ctype FLAG_##nam = def;
// We need to define all of our default values so that the Flag structure can
// access them by pointer. These are just used internally inside of one .cc,
// for MODE_META, so there is no impact on the flags interface.
#define FLAG_FULL(ftype, ctype, nam, def, cmt) \
static ctype const FLAGDEFAULT_##nam = def;
// We want to write entries into our meta data table, for internal parsing and
// printing / etc in the flag parser code. We only do this for writable flags.
#elif defined(FLAG_MODE_META)
#define FLAG_FULL(ftype, ctype, nam, def, cmt) \
{ Flag::TYPE_##ftype, #nam, &FLAG_##nam, &FLAGDEFAULT_##nam, cmt, false } \
#define FLAG_ALIAS(ftype, ctype, alias, nam) \
{ \
Flag::TYPE_##ftype, #alias, &FLAG_##nam, &FLAGDEFAULT_##nam, \
"alias for --" #nam, false \
} \
// We produce the code to set flags when it is implied by another flag.
#define DEFINE_IMPLICATION(whenflag, thenflag) \
if (FLAG_##whenflag) FLAG_##thenflag = true;
#define DEFINE_NEG_IMPLICATION(whenflag, thenflag) \
if (FLAG_##whenflag) FLAG_##thenflag = false;
#error No mode supplied when including flags.defs
// Dummy defines for modes where it is not relevant.
#ifndef FLAG_FULL
#define FLAG_FULL(ftype, ctype, nam, def, cmt)
#define FLAG_READONLY(ftype, ctype, nam, def, cmt)
#ifndef FLAG_ALIAS
#define FLAG_ALIAS(ftype, ctype, alias, nam)
#define DEFINE_IMPLICATION(whenflag, thenflag)
#define DEFINE_NEG_IMPLICATION(whenflag, thenflag)
#define COMMA ,
// Structure used to hold a collection of arguments to the JavaScript code.
struct JSArguments {
inline const char*& operator[](int idx) const { return argv[idx]; }
static JSArguments Create(int argc, const char** argv) {
JSArguments args;
args.argc = argc;
args.argv = argv;
return args;
int argc;
const char** argv;
struct MaybeBoolFlag {
static MaybeBoolFlag Create(bool has_value, bool value) {
MaybeBoolFlag flag;
flag.has_value = has_value;
flag.value = value;
return flag;
bool has_value;
bool value;
#define ENABLE_VFP3_DEFAULT true
#define ENABLE_VFP3_DEFAULT false
#define ENABLE_ARMV7_DEFAULT false
#if (defined CAN_USE_VFP32DREGS) || !(defined ARM_TEST_NO_FEATURE_PROBE)
#define ENABLE_32DREGS_DEFAULT false
#if (defined CAN_USE_NEON) || !(defined ARM_TEST_NO_FEATURE_PROBE)
# define ENABLE_NEON_DEFAULT false
#define DEFINE_BOOL(nam, def, cmt) FLAG(BOOL, bool, nam, def, cmt)
#define DEFINE_MAYBE_BOOL(nam, cmt) \
FLAG(MAYBE_BOOL, MaybeBoolFlag, nam, {false COMMA false}, cmt)
#define DEFINE_INT(nam, def, cmt) FLAG(INT, int, nam, def, cmt)
#define DEFINE_FLOAT(nam, def, cmt) FLAG(FLOAT, double, nam, def, cmt)
#define DEFINE_STRING(nam, def, cmt) FLAG(STRING, const char*, nam, def, cmt)
#define DEFINE_ARGS(nam, cmt) FLAG(ARGS, JSArguments, nam, {0 COMMA NULL}, cmt)
#define DEFINE_ALIAS_BOOL(alias, nam) FLAG_ALIAS(BOOL, bool, alias, nam)
#define DEFINE_ALIAS_INT(alias, nam) FLAG_ALIAS(INT, int, alias, nam)
#define DEFINE_ALIAS_FLOAT(alias, nam) FLAG_ALIAS(FLOAT, double, alias, nam)
#define DEFINE_ALIAS_STRING(alias, nam) \
FLAG_ALIAS(STRING, const char*, alias, nam)
#define DEFINE_ALIAS_ARGS(alias, nam) FLAG_ALIAS(ARGS, JSArguments, alias, nam)
// Flags in all modes.
// Flags for language modes and experimental language features.
DEFINE_BOOL(use_strict, false, "enforce strict mode")
DEFINE_BOOL(es_staging, false, "enable upcoming ES6+ features")
DEFINE_BOOL(harmony_scoping, false, "enable harmony block scoping")
DEFINE_BOOL(harmony_modules, false,
"enable harmony modules (implies block scoping)")
DEFINE_BOOL(harmony_proxies, false, "enable harmony proxies")
DEFINE_BOOL(harmony_generators, false, "enable harmony generators")
DEFINE_BOOL(harmony_numeric_literals, false,
"enable harmony numeric literals (0o77, 0b11)")
DEFINE_BOOL(harmony_strings, false, "enable harmony string")
DEFINE_BOOL(harmony_arrays, false, "enable harmony arrays")
DEFINE_BOOL(harmony_arrow_functions, false, "enable harmony arrow functions")
DEFINE_BOOL(harmony, false, "enable all harmony features (except proxies)")
DEFINE_IMPLICATION(harmony, harmony_scoping)
DEFINE_IMPLICATION(harmony, harmony_modules)
// TODO(rossberg): Reenable when problems are sorted out.
// DEFINE_IMPLICATION(harmony, harmony_proxies)
DEFINE_IMPLICATION(harmony, harmony_generators)
DEFINE_IMPLICATION(harmony, harmony_numeric_literals)
DEFINE_IMPLICATION(harmony, harmony_strings)
DEFINE_IMPLICATION(harmony, harmony_arrays)
DEFINE_IMPLICATION(harmony, harmony_arrow_functions)
DEFINE_IMPLICATION(harmony_modules, harmony_scoping)
DEFINE_IMPLICATION(harmony, es_staging)
// Flags for experimental implementation features.
DEFINE_BOOL(compiled_keyed_dictionary_loads, true,
"use optimizing compiler to generate keyed dictionary load stubs")
DEFINE_BOOL(compiled_keyed_generic_loads, false,
"use optimizing compiler to generate keyed generic load stubs")
DEFINE_BOOL(clever_optimizations, true,
"Optimize object size, Array shift, DOM strings and string +")
// TODO(hpayer): We will remove this flag as soon as we have pretenuring
// support for specific allocation sites.
DEFINE_BOOL(pretenuring_call_new, false, "pretenure call new")
DEFINE_BOOL(allocation_site_pretenuring, true,
"pretenure with allocation sites")
DEFINE_BOOL(trace_pretenuring, false,
"trace pretenuring decisions of HAllocate instructions")
DEFINE_BOOL(trace_pretenuring_statistics, false,
"trace allocation site pretenuring statistics")
DEFINE_BOOL(track_fields, true, "track fields with only smi values")
DEFINE_BOOL(track_double_fields, true, "track fields with double values")
DEFINE_BOOL(track_heap_object_fields, true, "track fields with heap values")
DEFINE_BOOL(track_computed_fields, true, "track computed boilerplate fields")
DEFINE_IMPLICATION(track_double_fields, track_fields)
DEFINE_IMPLICATION(track_heap_object_fields, track_fields)
DEFINE_IMPLICATION(track_computed_fields, track_fields)
DEFINE_BOOL(track_field_types, true, "track field types")
DEFINE_IMPLICATION(track_field_types, track_fields)
DEFINE_IMPLICATION(track_field_types, track_heap_object_fields)
DEFINE_BOOL(smi_binop, true, "support smi representation in binary operations")
DEFINE_BOOL(vector_ics, false, "support vector-based ics")
// Flags for optimization types.
DEFINE_BOOL(optimize_for_size, false,
"Enables optimizations which favor memory size over execution "
// Flags for data representation optimizations
DEFINE_BOOL(unbox_double_arrays, true, "automatically unbox arrays of doubles")
DEFINE_BOOL(string_slices, true, "use string slices")
// Flags for Crankshaft.
DEFINE_BOOL(crankshaft, true, "use crankshaft")
DEFINE_STRING(hydrogen_filter, "*", "optimization filter")
DEFINE_BOOL(use_gvn, true, "use hydrogen global value numbering")
DEFINE_INT(gvn_iterations, 3, "maximum number of GVN fix-point iterations")
DEFINE_BOOL(use_canonicalizing, true, "use hydrogen instruction canonicalizing")
DEFINE_BOOL(use_inlining, true, "use function inlining")
DEFINE_BOOL(use_escape_analysis, true, "use hydrogen escape analysis")
DEFINE_BOOL(use_allocation_folding, true, "use allocation folding")
DEFINE_BOOL(use_local_allocation_folding, false, "only fold in basic blocks")
DEFINE_BOOL(use_write_barrier_elimination, true,
"eliminate write barriers targeting allocations in optimized code")
DEFINE_INT(max_inlining_levels, 5, "maximum number of inlining levels")
DEFINE_INT(max_inlined_source_size, 600,
"maximum source size in bytes considered for a single inlining")
DEFINE_INT(max_inlined_nodes, 196,
"maximum number of AST nodes considered for a single inlining")
DEFINE_INT(max_inlined_nodes_cumulative, 400,
"maximum cumulative number of AST nodes considered for inlining")
DEFINE_BOOL(loop_invariant_code_motion, true, "loop invariant code motion")
DEFINE_BOOL(fast_math, true, "faster (but maybe less accurate) math functions")
DEFINE_BOOL(collect_megamorphic_maps_from_stub_cache, true,
"crankshaft harvests type feedback from stub cache")
DEFINE_BOOL(hydrogen_stats, false, "print statistics for hydrogen")
DEFINE_BOOL(trace_check_elimination, false, "trace check elimination phase")
DEFINE_BOOL(trace_hydrogen, false, "trace generated hydrogen to file")
DEFINE_STRING(trace_hydrogen_filter, "*", "hydrogen tracing filter")
DEFINE_BOOL(trace_hydrogen_stubs, false, "trace generated hydrogen for stubs")
DEFINE_STRING(trace_hydrogen_file, NULL, "trace hydrogen to given file name")
DEFINE_STRING(trace_phase, "HLZ", "trace generated IR for specified phases")
DEFINE_BOOL(trace_inlining, false, "trace inlining decisions")
DEFINE_BOOL(trace_load_elimination, false, "trace load elimination")
DEFINE_BOOL(trace_store_elimination, false, "trace store elimination")
DEFINE_BOOL(trace_alloc, false, "trace register allocator")
DEFINE_BOOL(trace_all_uses, false, "trace all use positions")
DEFINE_BOOL(trace_range, false, "trace range analysis")
DEFINE_BOOL(trace_gvn, false, "trace global value numbering")
DEFINE_BOOL(trace_representation, false, "trace representation types")
DEFINE_BOOL(trace_removable_simulates, false, "trace removable simulates")
DEFINE_BOOL(trace_escape_analysis, false, "trace hydrogen escape analysis")
DEFINE_BOOL(trace_allocation_folding, false, "trace allocation folding")
DEFINE_BOOL(trace_track_allocation_sites, false,
"trace the tracking of allocation sites")
DEFINE_BOOL(trace_migration, false, "trace object migration")
DEFINE_BOOL(trace_generalization, false, "trace map generalization")
DEFINE_BOOL(stress_pointer_maps, false, "pointer map for every instruction")
DEFINE_BOOL(stress_environments, false, "environment for every instruction")
DEFINE_INT(deopt_every_n_times, 0,
"deoptimize every n times a deopt point is passed")
DEFINE_INT(deopt_every_n_garbage_collections, 0,
"deoptimize every n garbage collections")
DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points")
DEFINE_BOOL(trap_on_deopt, false, "put a break point before deoptimizing")
DEFINE_BOOL(trap_on_stub_deopt, false,
"put a break point before deoptimizing a stub")
DEFINE_BOOL(deoptimize_uncommon_cases, true, "deoptimize uncommon cases")
DEFINE_BOOL(polymorphic_inlining, true, "polymorphic inlining")
DEFINE_BOOL(use_osr, true, "use on-stack replacement")
DEFINE_BOOL(array_bounds_checks_elimination, true,
"perform array bounds checks elimination")
DEFINE_BOOL(trace_bce, false, "trace array bounds check elimination")
DEFINE_BOOL(array_bounds_checks_hoisting, false,
"perform array bounds checks hoisting")
DEFINE_BOOL(array_index_dehoisting, true, "perform array index dehoisting")
DEFINE_BOOL(analyze_environment_liveness, true,
"analyze liveness of environment slots and zap dead values")
DEFINE_BOOL(load_elimination, true, "use load elimination")
DEFINE_BOOL(check_elimination, true, "use check elimination")
DEFINE_BOOL(store_elimination, false, "use store elimination")
DEFINE_BOOL(dead_code_elimination, true, "use dead code elimination")
DEFINE_BOOL(fold_constants, true, "use constant folding")
DEFINE_BOOL(trace_dead_code_elimination, false, "trace dead code elimination")
DEFINE_BOOL(unreachable_code_elimination, true, "eliminate unreachable code")
DEFINE_BOOL(trace_osr, false, "trace on-stack replacement")
DEFINE_INT(stress_runs, 0, "number of stress runs")
DEFINE_BOOL(optimize_closures, true, "optimize closures")
DEFINE_BOOL(lookup_sample_by_shared, true,
"when picking a function to optimize, watch for shared function "
"info, not JSFunction itself")
DEFINE_BOOL(cache_optimized_code, true, "cache optimized code for closures")
DEFINE_BOOL(flush_optimized_code_cache, true,
"flushes the cache of optimized code for closures on every GC")
DEFINE_BOOL(inline_construct, true, "inline constructor calls")
DEFINE_BOOL(inline_arguments, true, "inline functions with arguments object")
DEFINE_BOOL(inline_accessors, true, "inline JavaScript accessors")
DEFINE_INT(escape_analysis_iterations, 2,
"maximum number of escape analysis fix-point iterations")
DEFINE_BOOL(optimize_for_in, true, "optimize functions containing for-in loops")
DEFINE_BOOL(opt_safe_uint32_operations, true,
"allow uint32 values on optimize frames if they are used only in "
"safe operations")
DEFINE_BOOL(concurrent_recompilation, true,
"optimizing hot functions asynchronously on a separate thread")
DEFINE_BOOL(trace_concurrent_recompilation, false,
"track concurrent recompilation")
DEFINE_INT(concurrent_recompilation_queue_length, 8,
"the length of the concurrent compilation queue")
DEFINE_INT(concurrent_recompilation_delay, 0,
"artificial compilation delay in ms")
DEFINE_BOOL(block_concurrent_recompilation, false,
"block queued jobs until released")
DEFINE_BOOL(concurrent_osr, true, "concurrent on-stack replacement")
DEFINE_IMPLICATION(concurrent_osr, concurrent_recompilation)
DEFINE_BOOL(omit_map_checks_for_leaf_maps, true,
"do not emit check maps for constant values that have a leaf map, "
"deoptimize the optimized code if the layout of the maps changes.")
// Flags for TurboFan.
DEFINE_STRING(turbo_filter, "~", "optimization filter for TurboFan compiler")
DEFINE_BOOL(trace_turbo, false, "trace generated TurboFan IR")
DEFINE_BOOL(trace_turbo_types, true, "trace generated TurboFan types")
DEFINE_BOOL(trace_turbo_scheduler, false, "trace generated TurboFan scheduler")
DEFINE_BOOL(turbo_verify, false, "verify TurboFan graphs at each phase")
DEFINE_BOOL(turbo_stats, false, "print TurboFan statistics")
DEFINE_BOOL(turbo_types, false, "use typed lowering in TurboFan")
DEFINE_BOOL(turbo_source_positions, false,
"track source code positions when building TurboFan IR")
DEFINE_BOOL(context_specialization, true,
"enable context specialization in TurboFan")
DEFINE_BOOL(turbo_deoptimization, false, "enable deoptimization in TurboFan")
DEFINE_INT(typed_array_max_size_in_heap, 64,
"threshold for in-heap typed array")
// Profiler flags.
DEFINE_INT(frame_count, 1, "number of stack frames inspected by the profiler")
// 0x1800 fits in the immediate field of an ARM instruction.
DEFINE_INT(interrupt_budget, 0x1800,
"execution budget before interrupt is triggered")
DEFINE_INT(type_info_threshold, 25,
"percentage of ICs that must have type info to allow optimization")
DEFINE_INT(generic_ic_threshold, 30,
"max percentage of megamorphic/generic ICs to allow optimization")
DEFINE_INT(self_opt_count, 130, "call count before self-optimization")
DEFINE_BOOL(trace_opt_verbose, false, "extra verbose compilation tracing")
DEFINE_IMPLICATION(trace_opt_verbose, trace_opt)
// / /
DEFINE_BOOL(debug_code, false, "generate extra code (assertions) for debugging")
DEFINE_BOOL(code_comments, false, "emit comments in code disassembly")
DEFINE_BOOL(enable_sse3, true, "enable use of SSE3 instructions if available")
DEFINE_BOOL(enable_sse4_1, true,
"enable use of SSE4.1 instructions if available")
DEFINE_BOOL(enable_sahf, true,
"enable use of SAHF instruction if available (X64 only)")
"enable use of VFP3 instructions if available")
"enable use of ARMv7 instructions if available (ARM only)")
"enable use of NEON instructions if available (ARM only)")
DEFINE_BOOL(enable_sudiv, true,
"enable use of SDIV and UDIV instructions if available (ARM only)")
DEFINE_BOOL(enable_mls, true,
"enable use of MLS instructions if available (ARM only)")
DEFINE_BOOL(enable_movw_movt, false,
"enable loading 32-bit constant by means of movw/movt "
"instruction pairs (ARM only)")
DEFINE_BOOL(enable_unaligned_accesses, true,
"enable unaligned accesses for ARMv7 (ARM only)")
"enable use of d16-d31 registers on ARM - this requires VFP3")
DEFINE_BOOL(enable_vldr_imm, false,
"enable use of constant pools for double immediate (ARM only)")
DEFINE_BOOL(force_long_branches, false,
"force all emitted branches to be in long mode (MIPS only)")
DEFINE_BOOL(enable_always_align_csp, true,
"enable alignment of csp to 16 bytes on platforms which prefer "
"the register to always be aligned (ARM64 only)")
DEFINE_STRING(expose_natives_as, NULL, "expose natives in global object")
DEFINE_STRING(expose_debug_as, NULL, "expose debug in global object")
DEFINE_BOOL(expose_free_buffer, false, "expose freeBuffer extension")
DEFINE_BOOL(expose_gc, false, "expose gc extension")
DEFINE_STRING(expose_gc_as, NULL,
"expose gc extension under the specified name")
DEFINE_IMPLICATION(expose_gc_as, expose_gc)
DEFINE_BOOL(expose_externalize_string, false,
"expose externalize string extension")
DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension")
DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture")
DEFINE_BOOL(builtins_in_stack_traces, false,
"show built-in functions in stack traces")
DEFINE_BOOL(disable_native_files, false, "disable builtin natives files")
DEFINE_BOOL(inline_new, true, "use fast inline allocation")
// /
DEFINE_BOOL(trace_codegen, false,
"print name of functions for which code is generated")
DEFINE_BOOL(trace, false, "trace function calls")
DEFINE_BOOL(mask_constants_with_cookie, true,
"use random jit cookie to mask large constants")
DEFINE_BOOL(lazy, true, "use lazy compilation")
DEFINE_BOOL(trace_opt, false, "trace lazy optimization")
DEFINE_BOOL(trace_opt_stats, false, "trace lazy optimization statistics")
DEFINE_BOOL(opt, true, "use adaptive optimizations")
DEFINE_BOOL(always_opt, false, "always try to optimize functions")
DEFINE_BOOL(always_osr, false, "always try to OSR functions")
DEFINE_BOOL(prepare_always_opt, false, "prepare for turning on always opt")
DEFINE_BOOL(trace_deopt, false, "trace optimize function deoptimization")
DEFINE_BOOL(trace_stub_failures, false,
"trace deoptimization of generated code stubs")
DEFINE_BOOL(serialize_toplevel, false, "enable caching of toplevel scripts")
DEFINE_INT(min_preparse_length, 1024,
"minimum length for automatic enable preparsing")
DEFINE_BOOL(always_full_compiler, false,
"try to use the dedicated run-once backend for all code")
DEFINE_INT(max_opt_count, 10,
"maximum number of optimization attempts before giving up.")
DEFINE_BOOL(compilation_cache, true, "enable compilation cache")
DEFINE_BOOL(cache_prototype_transitions, true, "cache prototype transitions")
DEFINE_INT(cpu_profiler_sampling_interval, 1000,
"CPU profiler sampling interval in microseconds")
DEFINE_BOOL(trace_debug_json, false, "trace debugging JSON request/response")
DEFINE_BOOL(trace_js_array_abuse, false,
"trace out-of-bounds accesses to JS arrays")
DEFINE_BOOL(trace_external_array_abuse, false,
"trace out-of-bounds-accesses to external arrays")
DEFINE_BOOL(trace_array_abuse, false,
"trace out-of-bounds accesses to all arrays")
DEFINE_IMPLICATION(trace_array_abuse, trace_js_array_abuse)
DEFINE_IMPLICATION(trace_array_abuse, trace_external_array_abuse)
DEFINE_BOOL(enable_liveedit, true, "enable liveedit experimental feature")
DEFINE_BOOL(hard_abort, true, "abort by crashing")
"default size of stack region v8 is allowed to use (in kBytes)")
DEFINE_INT(max_stack_trace_source_length, 300,
"maximum length of function source code printed in a stack trace.")
DEFINE_BOOL(always_inline_smi_code, false,
"always inline smi code in non-opt code")
DEFINE_INT(min_semi_space_size, 0,
"min size of a semi-space (in MBytes), the new space consists of two"
DEFINE_INT(max_semi_space_size, 0,
"max size of a semi-space (in MBytes), the new space consists of two"
DEFINE_INT(max_old_space_size, 0, "max size of the old space (in Mbytes)")
DEFINE_INT(max_executable_size, 0, "max size of executable memory (in Mbytes)")
DEFINE_BOOL(gc_global, false, "always perform global GCs")
DEFINE_INT(gc_interval, -1, "garbage collect after <n> allocations")
DEFINE_BOOL(trace_gc, false,
"print one trace line following each garbage collection")
DEFINE_BOOL(trace_gc_nvp, false,
"print one detailed trace line in name=value format "
"after each garbage collection")
DEFINE_BOOL(trace_gc_ignore_scavenger, false,
"do not print trace line after scavenger collection")
DEFINE_BOOL(print_cumulative_gc_stat, false,
"print cumulative GC statistics in name=value format on exit")
DEFINE_BOOL(print_max_heap_committed, false,
"print statistics of the maximum memory committed for the heap "
"in name=value format on exit")
DEFINE_BOOL(trace_gc_verbose, false,
"print more details following each garbage collection")
DEFINE_BOOL(trace_fragmentation, false,
"report fragmentation for old pointer and data pages")
DEFINE_BOOL(collect_maps, true,
"garbage collect maps from which no objects can be reached")
DEFINE_BOOL(weak_embedded_maps_in_ic, true,
"make maps embedded in inline cache stubs")
DEFINE_BOOL(weak_embedded_maps_in_optimized_code, true,
"make maps embedded in optimized code weak")
DEFINE_BOOL(weak_embedded_objects_in_optimized_code, true,
"make objects embedded in optimized code weak")
DEFINE_BOOL(flush_code, true,
"flush code that we expect not to use again (during full gc)")
DEFINE_BOOL(flush_code_incrementally, true,
"flush code that we expect not to use again (incrementally)")
DEFINE_BOOL(trace_code_flushing, false, "trace code flushing progress")
DEFINE_BOOL(age_code, true,
"track un-executed functions to age code and flush only "
"old code (required for code flushing)")
DEFINE_BOOL(incremental_marking, true, "use incremental marking")
DEFINE_BOOL(incremental_marking_steps, true, "do incremental marking steps")
DEFINE_BOOL(trace_incremental_marking, false,
"trace progress of the incremental marking")
DEFINE_BOOL(track_gc_object_stats, false,
"track object counts and memory usage")
DEFINE_BOOL(always_precise_sweeping, true, "always sweep precisely")
DEFINE_BOOL(parallel_sweeping, false, "enable parallel sweeping")
DEFINE_BOOL(concurrent_sweeping, true, "enable concurrent sweeping")
DEFINE_INT(sweeper_threads, 0,
"number of parallel and concurrent sweeping threads")
DEFINE_BOOL(job_based_sweeping, false, "enable job based sweeping")
DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC")
DEFINE_BOOL(heap_profiler_trace_objects, false,
"Dump heap object allocations/movements/size_updates")
DEFINE_BOOL(use_idle_notification, true,
"Use idle notification to reduce memory footprint.")
DEFINE_BOOL(use_ic, true, "use inline caching")
DEFINE_BOOL(trace_ic, false, "trace inline cache state transitions")
DEFINE_BOOL(native_code_counters, false,
"generate extra code for manipulating stats counters")
DEFINE_BOOL(always_compact, false, "Perform compaction on every full GC")
DEFINE_BOOL(never_compact, false,
"Never perform compaction on full GC - testing only")
DEFINE_BOOL(compact_code_space, true,
"Compact code space on full non-incremental collections")
DEFINE_BOOL(incremental_code_compaction, true,
"Compact code space on full incremental collections")
DEFINE_BOOL(cleanup_code_caches_at_gc, true,
"Flush inline caches prior to mark compact collection and "
"flush code caches in maps during mark compact cycle.")
DEFINE_BOOL(use_marking_progress_bar, true,
"Use a progress bar to scan large objects in increments when "
"incremental marking is active.")
DEFINE_BOOL(zap_code_space, true,
"Zap free memory in code space with 0xCC while sweeping.")
DEFINE_INT(random_seed, 0,
"Default seed for initializing random generator "
"(0, the default, means to use system random).")
DEFINE_BOOL(use_verbose_printer, true, "allows verbose printing")
DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax")
DEFINE_BOOL(trace_parse, false, "trace parsing and preparsing")
//, and
DEFINE_BOOL(trace_sim, false, "Trace simulator execution")
DEFINE_BOOL(debug_sim, false, "Enable debugging the simulator")
DEFINE_BOOL(check_icache, false,
"Check icache flushes in ARM and MIPS simulator")
DEFINE_INT(stop_sim_at, 0, "Simulator stop after x number of instructions")
#if defined(V8_TARGET_ARCH_ARM64) || defined(V8_TARGET_ARCH_MIPS64)
DEFINE_INT(sim_stack_alignment, 16,
"Stack alignment in bytes in simulator. This must be a power of two "
"and it must be at least 16. 16 is default.")
DEFINE_INT(sim_stack_alignment, 8,
"Stack alingment in bytes in simulator (4 or 8, 8 is default)")
DEFINE_INT(sim_stack_size, 2 * MB / KB,
"Stack size of the ARM64 and MIPS64 simulator "
"in kBytes (default is 2 MB)")
DEFINE_BOOL(log_regs_modified, true,
"When logging register values, only print modified registers.")
DEFINE_BOOL(log_colour, true, "When logging, try to use coloured output.")
DEFINE_BOOL(ignore_asm_unimplemented_break, false,
"Don't break for ASM_UNIMPLEMENTED_BREAK macros.")
DEFINE_BOOL(trace_sim_messages, false,
"Trace simulator debug messages. Implied by --trace-sim.")
DEFINE_BOOL(stack_trace_on_illegal, false,
"print stack trace when an illegal exception is thrown")
DEFINE_BOOL(abort_on_uncaught_exception, false,
"abort program (dump core) when an uncaught exception is thrown")
DEFINE_BOOL(randomize_hashes, true,
"randomize hashes to avoid predictable hash collisions "
"(with snapshots this option cannot override the baked-in seed)")
DEFINE_INT(hash_seed, 0,
"Fixed seed to use to hash property keys (0 means random)"
"(with snapshots this option cannot override the baked-in seed)")
DEFINE_BOOL(profile_deserialization, false,
"Print the time it takes to deserialize the snapshot.")
// Regexp
DEFINE_BOOL(regexp_optimization, true, "generate optimized regexp code")
// Testing flags test/cctest/test-{flags,api,serialization}.cc
DEFINE_BOOL(testing_bool_flag, true, "testing_bool_flag")
DEFINE_MAYBE_BOOL(testing_maybe_bool_flag, "testing_maybe_bool_flag")
DEFINE_INT(testing_int_flag, 13, "testing_int_flag")
DEFINE_FLOAT(testing_float_flag, 2.5, "float-flag")
DEFINE_STRING(testing_string_flag, "Hello, world!", "string-flag")
DEFINE_INT(testing_prng_seed, 42, "Seed used for threading test randomness")
#ifdef _WIN32
DEFINE_STRING(testing_serialization_file, "C:\\Windows\\Temp\\serdes",
"file in which to testing_serialize heap")
DEFINE_STRING(testing_serialization_file, "/tmp/serdes",
"file in which to serialize heap")
"A filename with extra code to be included in"
" the snapshot (mksnapshot only)")
"A file to write the raw snapshot bytes to. "
"(mksnapshot only)")
DEFINE_STRING(raw_context_file, NULL,
"A file to write the raw context "
"snapshot bytes to. (mksnapshot only)")
DEFINE_STRING(startup_blob, NULL,
"Write V8 startup blob file. "
"(mksnapshot only)")
DEFINE_BOOL(profile_hydrogen_code_stub_compilation, false,
"Print the time it takes to lazily compile hydrogen code stubs.")
DEFINE_BOOL(predictable, false, "enable predictable mode")
DEFINE_NEG_IMPLICATION(predictable, concurrent_recompilation)
DEFINE_NEG_IMPLICATION(predictable, concurrent_osr)
DEFINE_NEG_IMPLICATION(predictable, concurrent_sweeping)
DEFINE_NEG_IMPLICATION(predictable, parallel_sweeping)
// Dev shell flags
DEFINE_BOOL(help, false, "Print usage message, including flags, on console")
DEFINE_BOOL(dump_counters, false, "Dump counters on exit")
DEFINE_BOOL(debugger, false, "Enable JavaScript debugger")
DEFINE_STRING(map_counters, "", "Map counters to a file")
"Pass all remaining arguments to the script. Alias for \"--\".")
// GDB JIT integration flags.
DEFINE_BOOL(gdbjit, false, "enable GDBJIT interface (disables compacting GC)")
DEFINE_BOOL(gdbjit_full, false, "enable GDBJIT interface for all code objects")
DEFINE_BOOL(gdbjit_dump, false, "dump elf objects with debug info to disk")
DEFINE_STRING(gdbjit_dump_filter, "",
"dump only objects containing this substring")
DEFINE_BOOL(force_marking_deque_overflows, false,
"force overflows of marking deque by reducing it's size "
"to 64 words")
DEFINE_BOOL(stress_compaction, false,
"stress the GC compactor to flush out bugs (implies "
// Debug only flags
#undef FLAG
#ifdef DEBUG
DEFINE_BOOL(enable_slow_asserts, false,
"enable asserts that are slow to execute")
// / / macro-assembler-*.cc
DEFINE_BOOL(print_source, false, "pretty print source code")
DEFINE_BOOL(print_builtin_source, false,
"pretty print source code for builtins")
DEFINE_BOOL(print_ast, false, "print source AST")
DEFINE_BOOL(print_builtin_ast, false, "print source AST for builtins")
DEFINE_STRING(stop_at, "", "function name where to insert a breakpoint")
DEFINE_BOOL(trap_on_abort, false, "replace aborts by breakpoints")
DEFINE_BOOL(print_builtin_scopes, false, "print scopes for builtins")
DEFINE_BOOL(print_scopes, false, "print scopes")
DEFINE_BOOL(trace_contexts, false, "trace contexts operations")
DEFINE_BOOL(gc_verbose, false, "print stuff during garbage collection")
DEFINE_BOOL(heap_stats, false, "report heap statistics before and after GC")
DEFINE_BOOL(code_stats, false, "report code statistics after GC")
DEFINE_BOOL(verify_native_context_separation, false,
"verify that code holds on to at most one native context after GC")
DEFINE_BOOL(print_handles, false, "report handles after GC")
DEFINE_BOOL(print_global_handles, false, "report global handles after GC")
// TurboFan debug-only flags.
DEFINE_BOOL(print_turbo_replay, false,
"print C++ code to recreate TurboFan graphs")
DEFINE_BOOL(print_interfaces, false, "print interfaces")
DEFINE_BOOL(print_interface_details, false, "print interface inference details")
DEFINE_INT(print_interface_depth, 5, "depth for printing interfaces")
DEFINE_BOOL(trace_normalization, false,
"prints when objects are turned into dictionaries.")
DEFINE_BOOL(trace_lazy, false, "trace lazy compilation")
DEFINE_BOOL(collect_heap_spill_statistics, false,
"report heap spill statistics along with heap_stats "
"(requires heap_stats)")
DEFINE_BOOL(trace_isolates, false, "trace isolate state changes")
// Regexp
DEFINE_BOOL(regexp_possessive_quantifier, false,
"enable possessive quantifier syntax for testing")
DEFINE_BOOL(trace_regexp_bytecodes, false, "trace regexp bytecode execution")
DEFINE_BOOL(trace_regexp_assembler, false,
"trace regexp macro assembler calls.")
// Logging and profiling flags
#undef FLAG
DEFINE_BOOL(log, false,
"Minimal logging (no API, code, GC, suspect, or handles samples).")
DEFINE_BOOL(log_all, false, "Log all events to the log file.")
DEFINE_BOOL(log_api, false, "Log API events to the log file.")
DEFINE_BOOL(log_code, false,
"Log code events to the log file without profiling.")
DEFINE_BOOL(log_gc, false,
"Log heap samples on garbage collection for the hp2ps tool.")
DEFINE_BOOL(log_handles, false, "Log global handle events.")
DEFINE_BOOL(log_snapshot_positions, false,
"log positions of (de)serialized objects in the snapshot.")
DEFINE_BOOL(log_suspect, false, "Log suspect operations.")
DEFINE_BOOL(prof, false,
"Log statistical profiling information (implies --log-code).")
DEFINE_BOOL(prof_browser_mode, true,
"Used with --prof, turns on browser-compatible mode for profiling.")
DEFINE_BOOL(log_regexp, false, "Log regular expression execution.")
DEFINE_STRING(logfile, "v8.log", "Specify the name of the log file.")
DEFINE_BOOL(logfile_per_isolate, true, "Separate log files for each isolate.")
DEFINE_BOOL(ll_prof, false, "Enable low-level linux profiler.")
DEFINE_BOOL(perf_basic_prof, false,
"Enable perf linux profiler (basic support).")
DEFINE_NEG_IMPLICATION(perf_basic_prof, compact_code_space)
DEFINE_BOOL(perf_jit_prof, false,
"Enable perf linux profiler (experimental annotate support).")
DEFINE_NEG_IMPLICATION(perf_jit_prof, compact_code_space)
DEFINE_STRING(gc_fake_mmap, "/tmp/__v8_gc__",
"Specify the name of the file for fake gc mmap used in ll_prof")
DEFINE_BOOL(log_internal_timer_events, false, "Time internal events.")
DEFINE_BOOL(log_timer_events, false,
"Time events including external callbacks.")
DEFINE_IMPLICATION(log_timer_events, log_internal_timer_events)
DEFINE_IMPLICATION(log_internal_timer_events, prof)
DEFINE_BOOL(log_instruction_stats, false, "Log AArch64 instruction statistics.")
DEFINE_STRING(log_instruction_file, "arm64_inst.csv",
"AArch64 instruction statistics log file.")
DEFINE_INT(log_instruction_period, 1 << 22,
"AArch64 instruction statistics logging period.")
DEFINE_BOOL(redirect_code_traces, false,
"output deopt information and disassembly into file "
"code-<pid>-<isolate id>.asm")
DEFINE_STRING(redirect_code_traces_to, NULL,
"output deopt information and disassembly into the given file")
DEFINE_BOOL(hydrogen_track_positions, false,
"track source code positions when building IR")
// Disassembler only flags
#undef FLAG
DEFINE_BOOL(trace_elements_transitions, false, "trace elements transitions")
DEFINE_BOOL(trace_creation_allocation_sites, false,
"trace the creation of allocation sites")
DEFINE_BOOL(print_code_stubs, false, "print code stubs")
DEFINE_BOOL(test_secondary_stub_cache, false,
"test secondary stub cache by disabling the primary one")
DEFINE_BOOL(test_primary_stub_cache, false,
"test primary stub cache by disabling the secondary one")
// /
DEFINE_BOOL(print_code, false, "print generated code")
DEFINE_BOOL(print_opt_code, false, "print optimized code")
DEFINE_BOOL(print_unopt_code, false,
"print unoptimized code before "
"printing optimized code based on it")
DEFINE_BOOL(print_code_verbose, false, "print more information for code")
DEFINE_BOOL(print_builtin_code, false, "print generated code for builtins")
DEFINE_BOOL(sodium, false,
"print generated code output suitable for use with "
"the Sodium code viewer")
DEFINE_IMPLICATION(sodium, print_code_stubs)
DEFINE_IMPLICATION(sodium, print_code)
DEFINE_IMPLICATION(sodium, print_opt_code)
DEFINE_IMPLICATION(sodium, hydrogen_track_positions)
DEFINE_IMPLICATION(sodium, code_comments)
DEFINE_BOOL(print_all_code, false, "enable all flags related to printing code")
DEFINE_IMPLICATION(print_all_code, print_code)
DEFINE_IMPLICATION(print_all_code, print_opt_code)
DEFINE_IMPLICATION(print_all_code, print_unopt_code)
DEFINE_IMPLICATION(print_all_code, print_code_verbose)
DEFINE_IMPLICATION(print_all_code, print_builtin_code)
DEFINE_IMPLICATION(print_all_code, print_code_stubs)
DEFINE_IMPLICATION(print_all_code, code_comments)
#ifdef DEBUG
DEFINE_IMPLICATION(print_all_code, trace_codegen)
// VERIFY_PREDICTABLE related flags
#undef FLAG
DEFINE_BOOL(verify_predictable, false,
"this mode is used for checking that V8 behaves predictably")
DEFINE_INT(dump_allocations_digest_at_alloc, 0,
"dump allocations digest each n-th allocation")
// Read-only flags
#undef FLAG
// assembler-arm.h
DEFINE_BOOL(enable_ool_constant_pool, V8_OOL_CONSTANT_POOL,
"enable use of out-of-line constant pools (ARM only)")
// Cleanup...
#undef FLAG_FULL
#undef FLAG
#undef COMMA